Drilling, boring, or other machine



April 6, 1954 Filed April 50, 1952 P."D- MIZE DRILLING, BORING, OR OTHER MACHINE 2 Sheets-Sheet l INVENTOR.

PAUL D A4125 -BY v ATTORNEY April 6, 1954 P. D. MlZE DRILLING, BORING, OR OTHER MACHINE 2 Sheets-Sheet 2 Filed April 30, 1952 INVENTOR. P401. B 44/25 By MW A TTolA/EY Patented Apr. 6, i954 :i

"UNITED STATES F l C-E 2,674,138 DRILLING, BORING, OR' GTHER MACHINE Paul 1). Mize, Detroit, Mich. Application-AprilBO, 1952, Serial No. 285,190

1 This invention relates to power operated machine tools and more particularly to an improved method and means for controlling the traverse of a-drilling, boring or other-tool toward a and from the workpiece and for controlling the cutting rate or feed of the tool during the drill- *ing, boring'or'otheroperation. I

Few machine operators are manually able to control a drilling, boring or-other machine with 'the-efiiciency andpreciseness of operation necessary toproduce a high rate of production and to malintain high"quality-workmanship. Depending'on the-lcindof material being drilled, bored or otherwise being worked, the size-oi the tool "being used and the speed of rotation of the machine spindle, there is generally onecu-tting *feed rate that will give the optimum results. When manually controlled, the cutting feed'rate is subject to wide variations-from the-desired norm particularly when the same'operation has to be repeated a number of times. Accordingly, it is anobj'ectof the present invention to provide an improved construction and arrangement for controlling the traverse of the drilling, boring or other tool toward and from the workpiece and for controlling the cutting feed of the tool during the drilling, boring or other operation, which improved construction and arrangement does not depend on the manual skill of the machme'operator-to produce thedesired result.

the conventional manually operable drilling, boringorother-machine the machine spindle is operatively associated with a quill "in such a manner that the spindle while being rotatable relative to the quill is axially bodily shi'itable therewith, the quill generally being operativel-y movable through a rack and pinion mechanism. In its illustrated embodiments the present inventioncomprises animproved construction and arrangement wherein the quill controlling the axial movement of the spindle is in the form of a piston movable within a cylindrical portion of "the machine head, said piston having a portion subjected on one side thereof to air under pressure and-on theother side thereof to liquid under pressure, the pressure forces being in opposition to each other and the differential between the two pressure forces determining the direction and rate of axial movement of the piston and thespindle of the machine and there-- fore the direction and rate of axial movement o2 theoutting tool, suitable valve means being provided to-control' 'the'air and liquid new to and from the cylinder. In the illustrated embodi inents' the valve means controlling the liquid -9 Claims. (01. Ina-3315) "now comprises-'two separate valves located-in parallel conduits leading' fro'm the c'ylinderto a reservoirpone -of said valves being a metering valve and the other being a piston typevalve adapted *to be in either a fully opened enclosed position, 'saidpiston type valve being constructed and arranged to be acted upon at opposite ends by air and liquid P pressure forces, the differential between the two pressure forces "determining whether I the valve is in opened "or 'closed position relative to the liquid flow conduit in which it is located, and the opened-or closed position of this valve being determinative of the rate -of "axiakm'ovement ofthe cutting toohsince w-ith this {valve elosed the liquid can only flow "from the cylinder to the reservoir at the rate permitted by the setting of the metering valve.

Other features and objetswf the present invention will aIppear in the following-description and appended claims, reference being had to the accompanying drawings forming a part or this specification wherein likereference characters designate corres'ponding in the several views.

Fig. 1 is a diagrammatic view-partly inseotion illustrating one embodiment of the present invention in one condition ofaoperation.

Fig. 2 is a diagrammatic view in part simila'r to Fig. 1 illustrating the present invention in a second :condition of operation.

"Fig. -3 is a diagrammatic view' 'in part similar to Figs. 1 and' 2 illustrating' the present invention-in a third-condition of operation.

Fig. 4 is a tliagrainma'tic view partly section illustrating 'a second embodiment of the presla'nt invention.

Before explaining detail the present invention it to be understood that the invention is not limited in its application to the details 1 of cons'tru'ction and arrangement 'of parts illustrated in the accompanying -drawings, since the invention is capaldle of other embodiments of being practiced orca'rriedout in "various-ways. Also itis to be understood that the phraseology or terminology employed'he'r'ein is for the pur: pose or description and not 0f 'limitatioltl.

' In thedrawing's the invention illustrated in diagrammatic "form. in order "that the impofitaiit Jfeaitur'es"-ina y be described without the confusion; inherent in excessive detail. illustrated in Figs. 1"'to 3 ancmsive, the Construction and arrangement embodied in the present invention comprises a-chaniher or "reservoir H Whidhiirf-Q erab'l-y" would be located within the framework ofthe *head portion =df"ad 1 1li fling gamma tapping machine. The chamber or reservoir II is adapted to hold a quantity of liquid and as illustrated is shown about one-half full of oil. Most machine shops and factories are piped for air under pressure from a centrally located air compressor, the air pressure generally being about 100 p. s. i. A conduit i2 adapted to be connected to such a source of air under pressure is shown at the upper portion of the chamber or reservoir H. The air under pressure introduced into chamber or reservoir I I through conduit I2 exerts a pressure on the liquid in the reservoir for a purpose to be hereinafter explained. As also will be explained in detail, the chamber or reservoir II is also connected by conduit and valve systems to a cylinder I3 forming a part of the machine head. 7

In the conventional manually operable drilling, boring or other machine, the machine spindle is operatively associated with a quill in such a manner that the spindle while being rotatable relative to the quill is movable axially therewith, the quill generally being operatively movable through a rack and pinion mechanism. In the present invention, the spindle I4 is shown in operative relationship to a quill I5,,it being understood that the spindle I4 and quill I5 are operatively associated with each other in any conventional manner whereby the spindle is rotatable relative to the quill while at the same time being bodily shiftable along an axial direction therewith. It will also be understood that the spindle I4 is splined to a sheave for rotation thereby in a manner well known to the art. The foregoing explanation is deemed sufiicient since those features of construction form no part of the present invention.

The quill I5 in the present invention is in the form ofa piston having a head portion I6 equal in diameter to the bore of the cylinder I3 and a body portion I! of lesser diameter. One end I3a of the cylinder I3, the upper end as viewed in Figs. 1 to 3 inclusive, is connected by suitable conduit sections I8 and I9 to the upper portion of the chamber or reservoir II, the conduit sections I8 and I9 being coupled to each other through a piston type valve 20. The piston .2I of the valve 26 is illustrated as being shiftable to provide a passagewayfor air under pressure to flow from conduitI-8 to conduit I9 (Figs. 1 and 2) and then into the upper end I30: of the cylinder I3 or to permit air to be exhausted from the upper end In of the cylinder I3 through conduit l9 to the atmosphere (Fig. 3). The upper end j3a of the cylinder I3 is connected by a conduit 22 to a second piston type valve 23 for a, purpose to be hereinafter explained.

The lower end I3b of the cylinder I3 has connected thereto a conduit 24 which divides into two branches 25 and 26, each of which terminates at the lower or liquid containing portion of the chamber or reservoir II. The conduit 25 has inserted therein a metering or needle valve 21 which is adjustable to provide any desired rate of flow. The conduit 26 directs the liquid flowing through it through the aforementioned piston valve 23. The piston 28 of the piston valve 23 is free floating within the valve body and is subjected at one end, the lower end as viewed in Figs. 1 to 3 inclusive, to air pressure from the conduit 22 and at its upper end to the liquid pressure within the conduit 26, the pressure differential between the air and liquidpressures being determinative as to whether the valve is pen as in F sla d 3 thereby perm t quid 4 flow in conduit 26 or closed as in Fig. 2 thereby not permitting any flow in conduit 26.

Referring to Fig. 1, it will be assumed that it is desired to drill a hole in a workpiece 29 which has been properly positioned, for example, under a drill 36 suitably chucked to the lower end of the spindle I4. It is immaterial to the present invention whether the machine spindle is rotating before engaging the work surface or is started to rotate upon coming in contact with the work surface. The piston 2I of the valve 20, which after the completion of the prior drilling operation is in the position shown in Fig. 3, is shifted to connect conduits I8 and 20 thereby admitting air under pressure to the end I3a of the cylinder I3. The effective area of the side I'6a of piston head I6 against which the air pressure is exerted is substantially equal to the piston head area less the cross sectional area of the sleeve 3| housing the upper portion of the spindle. It will be noted that the effective area of the side I 612 of the piston head I6 with which the liquid or oil in the cylinder is in contact is equal to the area of the piston less the cross sectional area of the quill body II, therefore the effective area of the side I 6b is substantially less than that of the side I611. The respective efiective areas are such that the force resulting from the air pressure is sufficient to overcome the resistant force of the liquid pressure and thus force the liquid through conduit 22 toward the chamber or reservoir II against the pressure of the air on the liquid surface. At the stage shown in Fig. 1 the liquid flowing from conduit 24 is flowing toward chamber II through conduit branches 25 and 26. At this stage the downward movement of the tool 36 toward the workpiece is relatively rapid inasmuch as the valve 23 permits a rapid discharge of the liquid or oil through the conduit 26. The piston 28 of the valve 23 has been described as being subjected to the opposed pressures of the air in conduit 22 and the liquid in conduit 26. It will be noted that the effective area of the piston surface in contact with the liquid in conduit 26 is somewhat less than the eifective' area of the piston surface in contact with the air coming from conduit 24. These effective areas have been so selected that during the free downward traverse of the drill toward the workpiece the force tending to maintain the piston 28 in open position and thereby to permit the flow of liquid in conduit 26 is greater than the force tending to urge the piston 28 into position to close conduit 26. It will be readily understood that because of the I expanding volume of the cylinder space above the piston head 16 as the quill I5 moves downwardly-the air pressure in conduit 22 will be sub stantially less than that in conduit I 9.

As soon as the drill 36 engages the surface of the workpiece 29 the free movement of the piston I5 in the cylinder I3 is retarded. Upon the drill engaging the workpiece surface not only does the rate of volumetric expansion of the space above the piston head l6 decrease permitting a pressure buildup in this space as well as in the conduit 22 but also the rate of volumetric contraction of the space under the piston head I6 decreases permitting a pressure fall off in this space as well as in the conduit 24 and its branches 25 and 26. Immediately upon the air pressure in conduit 22 increasing and the liquid pressure in conduit 26 decreasing, the force tending to move piston 28 in valve 23 into closing position relative to conduit 26 is sufiicient to overcome the force of the liquid pressure tending to maintain the piston 28 in open position and the valve olosesmsi shown Figt 2t ficcerdinglwtheonly: way through which liquid can: escape from the underside: 16b 01: piston" headl-Bis'=' through branch conduit" 25 and the rate of i nowthroughthis conduit: is li'mit'e'd by the-metering valve 2 1:- The degreeo!" opening of'meter'in'g valve 2 'l thu's 'determines 'the: cutting feed of the tool on as" illustratedithe drill:

To re't'rac't the: drill, the machine' operator -need throng-demonic 19 to th'e atmosphereas shown 09611 permitting Oil undervpressure to fiow id'fiidl-SF through conduit 2-6 F from the: reservoir I pinto-thee lowr'ehd I35 of the cylinder l 3 and'tlieleby raise:- the quill I 5 and 'the spindle- I 4,-thus' retracting-the; tour-co from the workpiece 29.

In the embodiment of the invention illu 'strated in -Fi'g; 4-; the liquidand air in the chamber H are shown separated bya spring loadeddiaphragm- 323 The use of the diaphragm perm-its th'e pressure-of the air to be transmitted to the o'il with--- out being'in contact therewith thus permittingthe'machine header the-chamber or'r'eservoir-l'l to=be tiltedfromthe position shownin Figs; 1 t0 3- inclusive-without disturbingthe effectiverela-- tionship between-the liquid and air in the chamher but otherwise-has no important-efiect on the mode of operation embodied in the present -in--- vention;

' Thus, the" present invention embodies acon struction and arrangement which'willemciently; and efi'ectively controlthe cutting feed of a drill in'g, boring or other-tool. Yetthe control of the cutting feed does not occur-until-the tool actually reaches the surface of the workpiece thus using the workpiece itself as' the guage initiating the changeof therate of axial movement of thema chine spindle from relatively rapid'traverse to cutting feed rate. Further; the metering valveonce set ensures the precisenessof thec'utting operation irregardless of how many'times it must 1 be repeated, thusensuring longer tool'lif'e and higher quality production.

I' claim:

'6 thereby "tel-force: all' thetllquid being: discharged f-romsald cylinder t'o -pass? onlyzthroughthb imatering valve.v v

2. A machinetoolcomprising a main toola hea-d including: a cylinder,v an. axially slidable" quill within v said: cylinder, a spindle 1' rotatable. within said 'quilL' and bodily; displaceable-therewith; a tool carried by said-spindle," an air conduitxmeans connected-at on'el 'end' to a: source ofa airrunde'r pressure and at-fits} other end to one end-of said cylinderr'a" liquid conduit means'iconnected' atone 8116 170 2. source I'of. liquid under pressure andaat its-'- other "end to the other endof said: cylinder;

' said: quill: having. a part thereof one" sunface' oi' which- 4s iincontact with" the air under pressure and: thecoppo'site .surIa-ce "of which is in contact -withtheliquidiunder-"pressure, the effective-area 1 of said-one surfacesbeinggreater' than the-:effec tive area of said opposite surface wherebwthe torc'e 'exer'ted byr'the air under pressure is-isumcient toi overcome the-resistant force-of the liquld under pressure andrcause axial-movement ofthe quill and-spindle toward a workpiece and also thedischarg'e of said liquid from said cylinder,

-the rate" of movement of I said quill and spindle being governed by; the rate of liquid discharge from said cylinden said' liquid conduit: means includingparallel'branch conduits one o'fwhich has: a meterlng valve therein and the-other of which'has" a valve responsive tochanges rin the force differential between-said air-and liquid-pressures. said last mentioned valvebeing adapted upon the change in the force differential between saidair and liquid pressure means-upon the addi tion to the latter of' the-resistant force resulting from the engagement of the. tool with: thework v piece to prevent the flow of liquid throughits branch' conduit and thereby restrict'the flow tor-a predetermined rate'as set by the metering valve;

3. The methodof controlling the axial mov ement of amachineitool spindlewhich-is rotatablymounted in aquill and is-bodily shiftabletherewithgsaid quill being confined within. a cylinder, which: comprises exerting air and liquid pressure unopposed surfaces respectively: of said qu-illso that the product of theair pressure and the area otthe-surface against which it actslwillproduce Nforce: suflioient to overcometheopposing force 1'. In a machine tool, a chamber partiallyfilled with" liquid and adapted to be connected 'to a v source of air underpressu're, a cylindery'a com-'- bination quill and piston axially slidable withi'rr' said cylinder, a tool holding spindle rotatablewithin said quill and bodily displaceable there'- with','air conduitme'ans connecting the'air filled: portion of said chamber with one end of said cylinder; and liquid conduit means connecting-the liquid filled portion of said chamber with the other'end of said cylinder, the piston portion of. said combination quill and piston having-one'sur face thereof in contact with the air and an op posits surface in contact with the liquid, the:- effective area. of said on'e surfa'ce being greater than the eliectivearea of said opposite surface whereby theforce exerted-by the air pressure'tis sufilcient to'overc'ome the -resistant: force of the? liquid pressure and cause axial movementlof the quill and spindle and also the liquid to be dischargedfromsaid cylinder, said liquid conduit means including a metering valve and a second valve in parallel therewith, said second? valve being responsive t'o" changes in the force difl'erene tial between said air and liquid" pressures and beingadapted at a predetermined force difie'rential'to-change from an open to mime-position resulting fromthe productof the liquidpressure andthe areaof" the surface against which itlacts and cause axial movement of saidquill and spindle-ata predetermined rate, theliquid with in the confines of the cylinder being permitted to discharge therefrom through at least two branches of a discharge. conduit at'a relatively.

through one of the branch conduits while controlling the liquid discharge-aha predetermined regulatedrate through the other or. said. branch conduits thus affecting: the rate of axial move, ment of said quill and spindle.

4. Ina machine too1 ,.,a first=fluid pressure means for moving. atool in one direction-,ase'w ondz: fluid pressure meansresisting movement on saldatool in'said one directipngxsaidisecondsiluid 7 fluid pressure means including a discharge con-'- duit having twoparallel branches, one of said branches having a metering valve therein and the other of said branches having a pressure responsive valve therein, said metering valve being adjustable to regulate the flow of fluid through said one branch and said pressure responsive valve being adapted to permit either flow. or no flow of fluid through said other branch, said pressure responsive valve normally permitting fluid to flow therethrough, means connecting said pressure responsive valve to said first fluid pressure means so that said pressure responsive valve will cut off the flow of fluid through said other "branch upon an increase of the pressure exerted by said first fluid pressure means due to the increase in resistance to movement of the tool in said one direction upon the same engaging a workpiece.

5. In a machine tool, a first fluid pressure means for moving a tool in one direction, a second fluid pressure means resisting movement of said tool in said one direction, the rate of movement of said tool being proportional to the force diflerential between the two fluid pressure means, said second fluid pressure means including a dis.- charge conduit having two parallel branches, one of said branches having a metering valve therein and the other of said branches having a pressure responsive valve therein, said metering valve being adjustable to regulate the flow of fluid through said one branch and said pressure responsive valve being adapted to permit either flow or no flow of fluid through said other branch, said pressure responsive valve normally permitting fluid flow therethrough, means connecting said pressure responsive valve to said first fluid pressure means so that said pressure responsive valve will cut off the flow of fluid through said other branch upon an increase of the pressure exerted by said first fluid pressure means due to the increase in resistance of movement of the tool in said one direction upon the same engaging a workpiece, T v

6. In a machine tool, air pressure means for moving a tool in one direction, liquid pressure means resisting movement of said tool in said one direction, said liquid pressure means'including a discharge conduit having two parallel branches, one of said branches having a metering valve therein adjustable to regulate the rate of flow of the fluid therethrough, the other of said branches having a pressure responsive valve therein normally permitting liquid: flow through said other branch, means connectin said pressure responsive valve to said air pressure means so that upon an increase of the pressure thereof to a predetermined pressure said pressure responsive valve will cut off the flow of fluid through said second branch and thus limit the now of fluid to the branch containing the metering valve. '7. A machine tool including a cylinder means, piston means within said cylinder movable in opposite directions by fluid under pressure, tool means connected to said piston, a source of fluid under pressure, a first conduit means for con-' veying fluid to and from one end of said cylinder, at second conduit means for conveying fluid to and from the other end of said cylinder, said fluid when being conveyed to said one end of the cylinder through said first conduit means creating a force on the piston suflicient to overcome-the resistant force of the fluid in the other end of said cylinder thereby to cause movement of said tool means toward a workpieceand-also' the discharge oi liquid from said other end of the cylinder through said second conduit means, the rate of movement of the tool toward said workpiece being proportional to the rate of discharge of fluid through said second conduit means, said second conduit means including a metering valve in parallel with a pressure responsive valve, the latter normally bein in an open condition, means connecting said pressure responsive valve to said one end of said cylinder, said pressure valve being responsive to an increase in pressure in said-one end of said cylinder whereby said pressure valve will close and the discharging fluid will be limited to flowing through said metering valve.

8. A machine tool comprising a cylinder means, piston means within said cylinder, means for connecting a tool to said piston means, air conduit means connecting a source of air under pres sure to one end of said cylinder, liquid conduit means connecting a source of liquid under pressure to the other end of said cylinder, the effective area of the side of the piston in contact with the air under pressure being greater than the effective area of the side thereof in contact with the liquid under pressure whereby the force resulting from the air pressure is sufficient to overcome the resistant force of the liquid'pressure, the differential in said forces resulting in move ment of a tool toward a workpiece at a predetermined rate of movement and to cause fluid to be discharged from said cylinder through said liquid conduit means, said liquid conduit means dividing into two parallel branches, one of said branches having a metering valve adjustable to regulate the flow of liquid therethrough, the other of said branches having a pressure responsive valve normally in an open position to permit unobstructed liquid flow therethrough, means connecting said pressure responsive valve to said one end of the cylinder so that in response to an increase of pressure within said one end of the cylinder to a predetermined pressure said pressure responsive valve will close and thereby block the flow of liquid through said other liquid conduit branch and the rate of discharge of said liquid will be determined solely by the flow of fluid through said metering valve.

9. A machine tool comprising a cylinder means, piston means within said cylinder, means for connecting a tool to said piston means, air conduit means connecting a source of air under pressure to one end of said cylinder, liquid conduit means connecting a source of liquid under pressure to the other end of said cylinder, the eflective area ofthe side of the piston in contact with the air under pressure being greater than the effective area of the side thereof in contact with the liquid under pressure whereby the force resulting from the air pressure is sufficient to overcome the resistant force of the liquid pressure, the differential in said forces resulting in movement of a tool toward a workpiece at a predetermined rate of movement and to cause fluid to-be discharged from said cylinder through said liquid conduit means, the rate of movement of the tool toward the workpiece being controlled by the rate of discharge of said liquid, and control means for varying the rate of discharge of said liquid, said control means comprising a metering valve and a pressure responsive valve mounted in parallel branches of said liquid conduit means, said metering valve being adjustable to regulate the flow of liquid therethrough and said pressure operated valve being adapted to either permit the flow of liquid therethrough at a fixed rate or restrict such such flow in its entirety, said u pressure responsive valve normally being in an open position, means connecting said pressure responsive valve to said one end of the cylinder, said pressure responsive valve upon an increase of pressure within said one end of the cylinder becoming closed and thereby stopping the flow of fluid through said other branch so that the rate of discharge of the liquid will be determined sole= pgi 1y by the and said if) a flow of liquid through said one branch metering valve.

References Cited in the file of this patent Number UNITED STATES PATENTS 7 Name Date Reynders et a1 Aug. 12, 1902 Stacy Nov. 30. 1943 

